How is glass made?

Glass is everywhere around us - there's a high chance the screen you're reading this post from, is glass. It is basically molten sand.

The sand commonly used to make glass is comprised of small grains of quartz crystals, made up of molecules of silicon dioxide, which is also known as silica. When those molecules are heated to high enough temperatures, the sand melts and loses its crystalline structure, and as it cools it gains an entirely different structure. This structure is called amorph, which means it is between something liquid and solid. Because of this, glass is always something a bit "unstable" or "moving" on a molecular level.